#ifndef NAV_MESH_FILTER_H
#define NAV_MESH_FILTER_H

#include "mesh.h"
#include "../Settings.h"
#include <omp.h>

#include <Indoor/geo/Heading.h>
#include <Indoor/math/Distributions.h>

#include <Indoor/smc/Particle.h>
#include <Indoor/smc/filtering/ParticleFilter.h>
#include <Indoor/smc/filtering/ParticleFilterInitializer.h>
#include <Indoor/smc/filtering/resampling/ParticleFilterResamplingSimple.h>
#include <Indoor/smc/filtering/resampling/ParticleFilterResamplingKLD.h>
#include <Indoor/smc/filtering/estimation/ParticleFilterEstimationBoxKDE.h>
#include <Indoor/smc/filtering/estimation/ParticleFilterEstimationWeightedAverage.h>
#include <Indoor/smc/filtering/estimation/ParticleFilterEstimationMax.h>

#include <Indoor/navMesh/walk/NavMeshWalkSimple.h>
#include <Indoor/navMesh/walk/NavMeshWalkEval.h>
#include <Indoor/navMesh/walk/NavMeshWalkWifi.h>
#include <Indoor/navMesh/walk/NavMeshWalkWifiRegional.h>
#include <Indoor/navMesh/walk/NavMeshWalkUnblockable.h>
#include <Indoor/navMesh/walk/NavMeshWalkKLD.h>
#include <Indoor/navMesh/NavMeshRandom.h>

#include <Indoor/sensors/radio/WiFiMeasurements.h>
#include <Indoor/data/Timestamp.h>
#include <Indoor/sensors/radio/WiFiProbabilityFree.h>
#include <Indoor/sensors/activity/ActivityDetector.h>

#include <Indoor/math/divergence/KullbackLeibler.h>
#include <Indoor/sensors/radio/WiFiQualityAnalyzer.h>

struct MyState {

	/** the state's position (within the mesh) */
	MyNavMeshLocation pos;

	/** the state's heading */
	Heading heading;

	MyState() : pos(), heading(0) {;}

    MyState(Point3 p) : pos(p, nullptr), heading(0){;}

	MyState& operator += (const MyState& o) {
		pos.tria = nullptr;	// impossible
		pos.pos += o.pos.pos;
		return *this;
	}

	MyState& operator /= (const double val) {
		pos.tria = nullptr;	// impossible
		pos.pos /= val;
		return *this;
	}

	MyState operator * (const double val) const {
		MyState res;
		res.pos.pos = pos.pos * val;
		return res;
	}

    float getX(){
        return pos.pos.x;
    }

    float getY() {
        return pos.pos.y;
    }

    float getBinValue(const int dim) const {
        switch (dim) {
            case 0: return this->pos.pos.x;
            case 1: return this->pos.pos.y;
            case 2: return this->pos.pos.z;
            case 3: return this->heading.getRAD();
        }
        throw "cant find this value within the bin";
    }

};

struct MyControl {

	int numStepsSinceLastEval = 0;
	float headingChangeSinceLastEval = 0;

	void afterEval() {
		numStepsSinceLastEval = 0;
		headingChangeSinceLastEval = 0;
	}

    //wifi
    WiFiMeasurements wifi;

    //time
    Timestamp currentTime;

    //last estimation
    Point3 lastEstimate = Point3(26, 43, 7.5);

};

struct MyObservation {

    // pressure
    float sigmaPressure = 0.10f;
    float relativePressure = 0;

    //wifi
    WiFiMeasurements wifi;

    //time
    Timestamp currentTime;

    //activity
    Activity activity;

};

class MyPFInitUniform : public SMC::ParticleFilterInitializer<MyState> {

	const MyNavMesh* mesh;

public:

	MyPFInitUniform(const MyNavMesh* mesh) : mesh(mesh) {
		;
	}

    virtual void initialize(std::vector<SMC::Particle<MyState>>& particles) override {

		/** random position and heading within the mesh */
		Distribution::Uniform<float> dHead(0, 2*M_PI);
		MyNavMeshRandom rnd = mesh->getRandom();
        for (SMC::Particle<MyState>& p : particles) {
			p.state.pos = rnd.draw();
			p.state.heading = dHead.draw();
			p.weight = 1.0 / particles.size();
		}
	}

};

class MyPFInitFixed : public SMC::ParticleFilterInitializer<MyState> {

	const MyNavMesh* mesh;
	const Point3 pos;

public:

	MyPFInitFixed(const MyNavMesh* mesh, const Point3 pos) : mesh(mesh), pos(pos) {
		;
	}

    virtual void initialize(std::vector<SMC::Particle<MyState>>& particles) override {

		/** random position and heading within the mesh */
		Distribution::Uniform<float> dHead(0, 2*M_PI);
        for (SMC::Particle<MyState>& p : particles) {
			p.state.pos = mesh->getLocation(pos);
			p.state.heading = dHead.draw();
			p.weight = 1.0 / particles.size();
		}
	}

};


class MyPFTrans : public SMC::ParticleFilterTransition<MyState, MyControl> {

    //using MyNavMeshWalk = NM::NavMeshWalkSimple<MyNavMeshTriangle>;
    //using MyNavMeshWalk = NM::NavMeshWalkWifiRegional<MyNavMeshTriangle>;
    //using MyNavMeshWalk = NM::NavMeshWalkUnblockable<MyNavMeshTriangle>;
    using MyNavMeshWalk = NM::NavMeshWalkKLD<MyNavMeshTriangle>;
	MyNavMeshWalk walker;

    WiFiQualityAnalyzer analyzer;
    WiFiObserverFree wifiProbability;
    const double lambda =  0.0003;

    SMC::ParticleFilterEstimationBoxKDE<MyState> estimator;

public:

    MyPFTrans(MyNavMesh& mesh, WiFiModel& wifiModel) :
        walker(mesh),
        wifiProbability(Settings::WiFiModel::sigma, wifiModel){

		// how to evaluate drawn points
        //walker.addEvaluator(new NM::WalkEvalHeadingStartEndNormal<MyNavMeshTriangle>(0.04));
        //walker.addEvaluator(new NM::WalkEvalDistance<MyNavMeshTriangle>(0.1));
        //walker.addEvaluator(new NM::WalkEvalApproachesTarget<MyNavMeshTriangle>(0.9));		// 90% for particles moving towards the target

        estimator = SMC::ParticleFilterEstimationBoxKDE<MyState>(&mesh, 0.2, Point2(1,1));

    }

    void transition(std::vector<SMC::Particle<MyState>>& particles, const MyControl* control) override {

        // walking and heading random
        Distribution::Normal<float> dStepSizeFloor(0.70, 0.1);
		Distribution::Normal<float> dStepSizeStair(0.35, 0.1);
        Distribution::Normal<float> dHeading(0.0, 0.1);

        // wifi and quality of wifi
        const WiFiMeasurements wifiObs = Settings::WiFiModel::vg_eval.group(control->wifi);
        if(!wifiObs.entries.empty()){
            analyzer.add(wifiObs);
        }
        float qualityWifi = analyzer.getQuality();
        if(std::isnan(qualityWifi)){
            qualityWifi = 1.0;
        } else if(qualityWifi == 0) {
            qualityWifi = 0.00000001;
        }

        // divergence between eval and transition
        std::vector<SMC::Particle<MyState>> wifiParticles;
        NM::NavMeshRandom<MyNavMeshTriangle> rnd = walker.getMesh().getRandom();
        for(int i = 0; i < 10000; ++i){

            NM::NavMeshLocation<MyNavMeshTriangle> tmpLocation = rnd.draw();
            double weight = wifiProbability.getProbability(tmpLocation.pos, control->currentTime, wifiObs);
            SMC::Particle<MyState> tmpParticle(MyState(tmpLocation.pos), weight);
            wifiParticles.push_back(tmpParticle);
        }

        MyState wifiEstimate = estimator.estimate(wifiParticles);

        // fake kld
        const double kld = control->lastEstimate.getDistance(wifiEstimate.pos.pos);
        //const double kld = Divergence::KullbackLeibler<double>::getMultivariateGauss(normParticle, normWifi);;

        //std::cout << "KLD: " << kld << std::endl;
        //std::cout << "Quality: " << qualityWifi << std::endl;

        //update wifi
        //walker.updateWiFi(wifiObs, control->currentTime, control->lastEstimate);

        #pragma omp parallel for num_threads(3)
        for (int i = 0; i < particles.size(); ++i) {
            SMC::Particle<MyState>& p = particles[i];

			// how to walk
			MyNavMeshWalkParams params;
			params.heading = p.state.heading + control->headingChangeSinceLastEval + dHeading.draw();
			params.numSteps = control->numStepsSinceLastEval;
			params.start = p.state.pos;

			params.stepSizes.stepSizeFloor_m = dStepSizeFloor.draw();
			params.stepSizes.stepSizeStair_m = dStepSizeStair.draw();

            if(params.stepSizes.stepSizeFloor_m < 0.1 || params.stepSizes.stepSizeStair_m < 0.1){
                params.stepSizes.stepSizeFloor_m  = 0.1;
                params.stepSizes.stepSizeStair_m  = 0.1;
            }

            double deltaUnblockable = 0.01;

			// walk
            //MyNavMeshWalk::ResultEntry res = walker.getOne(params);
            MyNavMeshWalk::ResultEntry res = walker.getOne(params, kld, lambda, qualityWifi);

			// assign back to particle's state
            p.weight *= res.probability;
			p.state.pos = res.location;
			p.state.heading = res.heading;

		}

		// reset the control (0 steps, 0 delta-heading)
		//control->afterEval();

	}


};

class MyPFEval : public SMC::ParticleFilterEvaluation<MyState, MyObservation> {

    WiFiModel& wifiModel;
    WiFiObserverFree wifiProbability;

    //TODO: add this to transition probability
    double getStairProb(const SMC::Particle<MyState>& p, const Activity act) {

        const float kappa = 0.75;

        switch (act) {

        case Activity::WALKING:
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::FLOOR_INDOOR)		{return kappa;}
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::DOOR)             {return kappa;}
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::STAIR_LEVELED)    {return kappa;}
                                                                                        {return 1-kappa;}

        case Activity::WALKING_UP:
        case Activity::WALKING_DOWN:
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::STAIR_SKEWED)		{return kappa;}
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::STAIR_LEVELED)    {return kappa;}
            if (p.state.pos.tria->getType() == (int) NM::NavMeshType::ELEVATOR)         {return kappa;}
                                                                                        {return 1-kappa;}
        }
        return 1.0;
    }

public:

    MyPFEval(WiFiModel& wifiModel) : wifiModel(wifiModel), wifiProbability(Settings::WiFiModel::sigma, wifiModel){}

    virtual double evaluation(std::vector<SMC::Particle<MyState>>& particles, const MyObservation& observation) override {

        double sum = 0;
        const WiFiMeasurements wifiObs = Settings::WiFiModel::vg_eval.group(observation.wifi);


        #pragma omp parallel for num_threads(3)
        for (int i = 0; i < particles.size(); ++i) {
            SMC::Particle<MyState>& p = particles[i];

            double pWifi = wifiProbability.getProbability(p.state.pos.pos, observation.currentTime, wifiObs);
            double pStair = getStairProb(p, observation.activity);

            //HACK HACK HACK HACK
            double prob = 1.0;
            prob = pWifi * pStair;

            p.weight *= prob;

            #pragma omp atomic
            sum += prob;
        }

        return sum;

	}

};


using MyFilter = SMC::ParticleFilter<MyState, MyControl, MyObservation>;


#endif